<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>26.Promise封装AJAX请求</title>
</head>

<body>
    <script>
        //接口地址： https://api.apiopen.top/getJoke 
        const p = new Promise((resolve, reject) => {
            //1. 创建AJAX对象
            const xhr = new XMLHttpRequest();
            //2. 初始化
            xhr.open('GET', 'https://api.apiopen.top/getJoke');
            //3.发送请求
            xhr.send();
            //4.绑定事件,处理响应结果
            xhr.onreadystatechange = function () {
                if (xhr.readyState === 4) {
                    //判断响应状态码 200-299 为成功
                    if (xhr.status >= 200 && xhr.status <= 300) {
                        resolve(xhr.response);
                    } else {
                        reject(xhr.status);
                    }
                }
            }
        })

        //指定回调
        p.then(function(value){
            console.log(value);
        },function(reason){
            console.error(reason);
        })
    </script>
</body>

</html>